Japanese Researcher: 2,600 Bq/Kg of Cesium-137 from Rice Grown on Soil Taken from Iitate-Mura

Kazue Tazaki is a professor emeritus at Kanazawa University in Ishikawa Prefecture. She took the contaminated soil from Iitate-mura in Fukushima Prefecture where the villagers were required to evacuate, and grew rice using that soil.

Rice planting and growing was banned in Iitate-mura this year.

Professor Tazaki just harvested the rice, and measured the concentration of cesium-137. The result?

• From the rice grains: 2,600 becquerels/kg

• From the straw: 2,200 becquerels/kg

• From the roots: 1,500 becquerels/kg

• Soil contamination: 50,000 becquerels/kg

Roughly an equal amount of cesium-134 is to be expected. The transfer rate of cesium-137 in this case was about 0.05.

From Toyama Shinbun, local paper in Ishikawa Prefecture (9/27/2011):

田崎和江金大名誉教授は２６日までに、高い放射線量が観測された福島県飯舘村の土を使って稲を栽培する実験を行い、収穫したコメから国の暫定基準値（１キロ当たり５００ベクレル）の５倍以上となる２６００ベクレルの放射性セシウムが検出されたとする結果をまとめた。同村は福島第１原発事故でコメの作付けが禁止されており、データは土壌の放射線量が農作物に与える影響を裏付ける重要な資料となる。

Kazue Tazaki, professor emeritus at Kanazawa University has compiled the result of her experiment of growing rice using the soil from Iitate-mura in Fukushima Prefecture where high radiation levels have been recorded. 2,600 becquerels/kg of radioactive cesium was detected from the harvested rice, more than 5 times the provisional safety limit (500 becquerels/kg) set by the national government. It was prohibited to plant rice in Iitate-mura because of the Fukushima I Nuclear Power Plant accident. The professor's data will be extremely valuable in studying the effect of radiation in the soil on the agricultural crops.

　田崎名誉教授は６月下旬に福島を訪れた際、高い放射線量を記録した飯舘村長泥地区の水田で土壌を採取。金沢市内の自宅で、この土壌に同市俵町で発芽させたコシヒカリの苗を植えた。

Professor Tazaki collected the soil from the rice paddies in Nagadoro District of Iitate-mura, area with very high radiation, when she visited Fukushima Prefecture in late June. At her home in Kanazawa City, she planted the seedlings of "Koshihikari" which were germinated in Tawara-machi in Kanazawa City on the soil from Iitate-mura.

　今月中旬に稲を刈り取り、北陸環境科学研究所（福井市）で各部分のセシウム１３７を分析し、１キロ当たりの線量を割り出した。その結果、籾米（もみごめ）からは、最も高い２６００ベクレルが検出された。わらは２２００ベクレル、根は１５００ベクレルで、土壌の線量は５万ベクレルだった。

She harvested the rice in mid September, had it analyzed at a laboratory in Fukui Prefecture for cesium-137 in various parts of the rice and calculated the radiation levels per kilogram. The highest cesium-137 concentration of 2,600 becquerels/kg was found in (unprocessed) rice, 2,200 becquerels/kg from the straw, and 1,500 becquerels/kg from the roots. 50,000 becquerels/kg was detected from the soil itself.

　比較のため、俵町の水田に植えたコシヒカリも分析したところ、放射性物質はまったく検出されなかった。

To compare, "Koshihikari" rice planted in the rice paddies in Tawara-machi was also analyzed but no radioactive materials were detected at all.

　田崎名誉教授は「可食部の放射線量が最も高くなり、私自身も衝撃を受けた。土壌の除染を急ぐ必要があるとあらためて感じる」と話した。２７日には福島県南相馬市で農家に能登の珪藻土（けいそうど）を使った除染方法などを指導する。

Professor Tazaki says, "I myself was very shocked to find that the edible part of the rice had the most radiation. The decontamination of the soil should be carried out as soon as possible". She will teach farmers in Minami Soma City in Fukushima on a decontamination method using diatomite unique to Ishikawa Prefecture.

Professor Tazaki found a bacterium that absorbs radioactive materials like uranium and thorium in Tanzania earlier this year, where she taught geology after she retired from Kanazawa University in 2009.

Her result makes me very suspicious of the results announced by Fukushima Prefecture. Iitate-mura does have high soil contamination but it is by no means the highest. Judging by the rice hay contamination there are many other locations within Fukushima that may have radiation levels just as high and still grow rice because they lie outside the 30 kilometer radius from the plant. And yet the prefectural government says it's found 500 becquerels/kg of radioactive cesium at most from one location, and the rest is below 200 becquerels/kg.

It is also possible that the professor scraped the top soil only, whereas farmers in Fukushima tilled deeper and thus mixing the highly contaminated soil in the top 5 centimeters with the uncontaminated soil below, lowering the overall radiation.

Well, despite the official ban with the threat of fines, the rice grew in Iitate-mura after all as at least one farmer spread the seed rice directly in the rice paddies. And as this Iitate-mura villager tweets, the rice has grown better than ever with far less work and resources. Why not test that too for radiation, instead of cutting it down?

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